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Flipping the direction of FanPressure BC

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Old   December 8, 2017, 06:02
Default Flipping the direction of FanPressure BC
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Matt Houchin
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I am trying to apply a fanPressure BC to an internal fan casing, using createBaffles.

I have created the baffles and applied the fanPressure boundary condition to the p field.

Everything is working correctly, except that the inlet flow is reversed, such that it behaves as an outlet (see attached image). I have tried changing the direction and the sign of the value in the fanPressure BC, but with no luck.

Has anyone been able to get the fanPressure direction to change?

p:

Code:
boundaryField
{
    atmosphereBoundary
    {
        type            fixedValue;
        value           uniform 0;
    }
    ductWork
    {
        type            zeroGradient;
    }
    fanCasing
    {
        type            zeroGradient;
    }
    plenumWall
    {
        type            zeroGradient;
    }
    systemBoundary
    {
        type            fixedValue;
        value           uniform 0;
    }
    baffle_master
    {
        type            fanPressure;
		fileName        "fanCurve";
		outOfBounds     clamp;
		direction       out;              // in | out
		p0              uniform 0;
		value           uniform 50;
		gamma			0;
    }
    baffle_slave
    {
        type            fanPressure;
		fileName        "fanCurve";
		outOfBounds     clamp;
		direction       in;              // in | out
		p0              uniform 0;
		value           uniform -50;
		gamma			0;
    }
}
createBafflesDict:

Quote:

internalFacesOnly true;

baffles
{
// NOTE: cyclicAMI patches MUST BE defined PRIOR to their associted
// blockage patches

baffle
{
//- Use predefined faceZone to select faces and orientation.
type faceZone;
zoneName fanSource;

patchPairs
{
type patch;
}
}
}
TopoSetDict:

Quote:
actions
(
{
name fanSource;
type faceZoneSet;
action new;
source searchableSurfaceToFaceZone;
sourceInfo
{
surface triSurfaceMesh;
name baffle.stl;
}
}
{
name fanSourceSlave;
type cellSet;
action new;
source faceZoneToCell;
sourceInfo
{
name fanSource;
option slave;
}
}
);
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Old   December 8, 2017, 06:49
Default Solved
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Matt Houchin
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For anyone wondering, I had my pressure boundary conditions entered in wrong.

Here is the correct boundary conditions to use:

p:

Quote:
boundaryField
{
atmosphereBoundary
{
type fixedValue;
value uniform 101325;
}
ductWork
{
type zeroGradient;
}
fanCasing
{
type zeroGradient;
}
plenumWall
{
type zeroGradient;
}
systemBoundary
{
type fixedValue;
value uniform 101375;
}
baffle_master
{
type fanPressure;
fileName "fanCurveOut";
outOfBounds clamp;
direction out; // in | out
p0 uniform 101325;
value uniform 101375;
gamma 0;
}
baffle_slave
{
type fanPressure;
fileName "fanCurveIn";
outOfBounds clamp;
direction in; // in | out
p0 uniform 101375;
value uniform 101325;
gamma 0;
}
}
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